I recently formatted a USB flash drive on my Mac (El-Capitan) and made a bootable Mojave installer drive. It worked great and there were no issues, until I needed to reformat it to use on Windows again. I've formatted the drive as FAT32 with a MBR partition and it reflects as such in the Disk Utility:

Drive: The screenshot of the drive settings

Partition: The screenshot of the partition settings

Windows Disk Management: The screenshot of Disk Management in Windows 10

CMD Diskpart -> list disk: The screenshot of the disks listed from diskpart.exe

For some reason, Windows doesn't even recognise that the drive is inserted into the PC. I'd expect to see a 16GB disk with no mountable volumes, instead I just see the same disk-listings that were there before I inserted the drive.

What frustrates me is that I've got experience with partitions and it's not usually rocket-science. The third image shows a hybrid drive with a MacOS partition (for my Macbook Air) that also contains a exFat partition for my media.

I've done this before many times over but can't, for the life of me, figure out why it's not working on this flash drive. Have I missed something really obvious? Am I losing my mind?

  • Did you try another USB port on your windows machine? – howdytom Jan 22 at 15:07
  • @howdytom Yes, I've tried on both front and rear ports on that particular machine as well as my NUC running Windows 7. In fact I had tried on the Win 7 NUC first and just assumed it was Windows acting up! – Daniel Jan 23 at 13:05
  • 1
    Try formating your USB flash drive again as HFS+ volume, first. Afterwards reformat it as FAT32. Do you see those issues with different USB drives as well? – howdytom Jan 23 at 16:39
  • @howdytom thanks, I'm trying that now. I've been using Mac & Windows for 5 years now and this is the first time I've encountered that issue – Daniel Jan 29 at 8:55
  • @howdytom your suggestion is confirmed as working. Please load it as an answer and I'll gladly accept it. Thanks so much for this suggestion! – Daniel Jan 29 at 10:58

Try formating your USB flash drive again as HFS+ volume, first. Afterwards reformat it as FAT32.

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.